I am sorry that I don't have insight into qrwpi/an. But I am incredibly curious: how did you get a copy of the Colloquia? Do you have en edition that is in the shape to be read and used? Or microfilm? It sounds like an interesting book.

unlikely suggestion but... I wonder whether this may just be a case of scribal omission or transposition, so that the word might be
something like [face=SPIonic]a0nqrwpina[/face], to agree with the [face=SPIonic]au0th[/face]..??

I'm still wondering what you're doing reading Possellius, arillio, but here is the answer.

Your sentence is found on page 5v under the topic 'Invitandi ad convivium'. These things are incredibly hard to read since the Greek font is still based on Manutius' type, which in turn relies on numerous scribal abbreviations. It helps to supplement with the Latin on the facing page. The confusion also resulted from the fact that the entire three lines within brackets makes up one sentence, so that qrwpian is actually the second half of a word that is hyphenated on the line above it. So here is how the actual sentence reads, as far as I can make out.